Nanjing University of Science & Technology

MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded RNA molecules that are typically 20-25 nucleotides in length. The expression levels of miRNAs in blood, tissue, and other samples are characteristically altered in several disease states. The detection of miRNAs represents a promising avenue for the early diagnosis of various diseases. Consequently, there is a clear need to enhance the sensitivity of miRNA detection to facilitate more accurate disease detection. A fluorescent biosensor was developed that utilizes supramolecular host-guest interactions for assembly and Mo-based materials to initiate a reversible addition-fragmentation chain transfer polymerization (RAFT). The scheme functions by modifying the miRNA on Fe₃O₄-magnetic nanoparticles (Fe₃O₄-MNPs), followed by linking the initiator of the subsequent RAFT reaction through supramolecular host-guest interaction. Ultimately, polymerization reactions initiated by Mo compounds result in the formation of polymers with fluorescent monomers on Fe₃O₄-MNPs. The sensor is extremely sensitive and the detection limit of this sensor is 0.03 fM. Furthermore, the protocol has been demonstrated to be highly effective in the detection of samples in serum, which also serves to illustrate the potential of this fluorescent biosensor for the detection of other kinds of miRNAs.

Alpha-fetoprotein (AFP) is a critical biomarker widely used for the screening and diagnosis of hepatocellular carcinoma and germ cell tumors. Although immunoassays are commonly employed for AFP detection, significant discrepancies in measurement results across different laboratories persist due to poor harmonization among methods. To improve the accuracy and harmonization of AFP quantification, this study developed a novel magnetic solid-phase extraction coupled with isotope dilution liquid chromatography-tandem mass spectrometry (MSPE-ID-LC-MS/MS) method for the precise measurement of AFP in serum. The method utilizes high-affinity AFP antibodies cocktails conjugated with magnetic nanoparticles to enhance the recovery of low-abundance AFP, combined with optimized elution conditions to ensure analytical reliability. The protocol involves one-step denaturation and alkylation, followed by tryptic digestion. This enables accurate quantification with SI-traceability using three signature peptides. Method validation demonstrated that intra- and inter-day precisions were <10 %, recovery rates of 99.8-101.4 %, and the limit of quantification (LOQ) of 1.5 ng/mL. This work establishes a metrologically robust reference procedure for AFP measurement and paves the way for standardization of clinical protein assays.

Developing high-efficiency bifunctional electrocatalysts capable of overcoming the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an urgent challenge for rechargeable zinc-air batteries (RZABs). Herein, we successfully prepared an excellent bifunctional catalysts through facile pyrolysis-free method. Nickel/iron layered double hydroxide (NiFe-LDH) with OER activity was in situ grown on carbon nanotubes (CNTs) and iron (II) phthalocyanine (FePc) with ORR activity was introduced through π-π interaction and covalent functionalization. Furthermore, the intervention of CNTs transform the electronic structure of NiFe-LDH to further enhance OER activity, while solve the problems of poor electrical conductivity and aggregation of FePc. The prepared bifunctional catalyst FePc-LDH@CNTs exhibits preeminent electrocatalystic performance for ORR (E_1/2 = 0.815 V) as well as OER (E_j=10 = 1.447 V). It displays a prominent bifunctionality which ΔE is only 0.632 V. Moreover, the liquid RZABs based on the FePc-LDH@CNTs demonstrate a significant specific capacity (810.4 mAh g^-1) and robust stability (840 h), superior to commerical Pt/C + RuO₂. As flexible RZABs, it maintains superb stability (100 h) and can drive water splitting to produce H₂ smoothly. In addition, the reasons for the failure are dissected by analyzing the components of the battery after cycles. This study provides a novel facile direction to prepare high-efficient and stable bifunctional oxygen electrocatalysts without pyrolysis.